Apparatus for electroslag remelting

ABSTRACT

A method of electroslag remelting of consumable electrodes characterized in that the agents improving the quality of the ingot are blown into the melt so that the injected flows of these agents cause rotation of this melt. A mould for electroslag remelting of consumable electrodes in the process of simultaneously blowing agents to the melt which improve the quality of the ingot, the mould being provided with at least one nozzle for blowing the agents into the melt, in which case the longitudinal axis of said nozzle is inclined to the walls of the mould under an angle other than a right angle. A consumable electrode provided with a nozzle for blowing agents into the melt to improve the quality of the ingot, which nozzle is made is the form of a coil wound on the electrode and made of the material being melted.

United States Patent 1191 Paton et al.

[ APPARATUS FOR ELECTROSLAG REMELTING [76] Inventors: Boris EvgenievichPaton, ulitsa Kotsjubinskogo, 5, kv. 21; Boris Izrailevich Theddvar,bulvar Lesi Ukrainki, 2, kv. 8; Jury Vadimovlch Latash, Vozdukhoflotskyprospekt,

81, kv. l4; Leonty Vasilievich Chekotilo, ulitsa Scherbakovke, 49a, kv.10; July Georgievich Emelyanenko, ulitsa Darvina, 5, kv. 5; VasilyIvandvich Us, ulitsa Saxaganskogo, 58, kv. l2; Vitaly MikhailovichBaglai, ulitsa Semashko, 10, kv. 54/3; Viktor Mikhailovich Martyn,ulitsa Vernadskogo, 65, kv. 102; Viktor Leonidovich Artamonov, ulitsaSovskaya, 9, kv. 4; Oleg Petrovich Bondarenko, ulitsa Kreschatik, 15,kv. 34; Georgy Alexandrovich Boiko, ulitsa 6, Libedskaya, 16, kv. 106;Anatoly Konstantinovich Tsikulenko, ulitsa Babushkina, 23, kv. 38;Vasily Vladimirovich Ivon, Darnitskol shosse, 107/2, kv. 16; LeonidViktorovich Pavlov, Borschagovskaya ulitsa, 234, kv. 6, all of Kiev,U.S.S.R.

Mar. 8, 1973 Appl. No.: 339,069

22 Filed:

[56] References Cited 1451 Apr. 16, 1974 [52] U.S. Cl. 164/252, 164/266[51] Int. Cl B22d 27/02 [58] Field of Search 164/52, 55, 56, 252, 266;13/9; 219/73, 126

UNITED STATES PATENTS 2,380,109 7/1945 Hopkins 164/52 3,200,232 8/1965Danhier ..219/73 FOREIGN PATENTS OR APPLICATIONS 968,248 9/1964 GreatBritain 219/126 Primary Examiner-J. Spencer Overholser AssistantExaminer-John E. Roethel Attorney, Agent, or Firm-Holman & Stern [5 7ABSTRACT A method of electroslag remelting of consumable electrodescharacterized in that the agents improving the quality of the ingot areblown into the melt so that the injected flows of these agents causerotation of this melt. A mould for electroslag remelting of consumableelectrodes in the process of simultaneously blowing agents to the meltwhich improve the quality-of the in- "got, the mould being provided withat least one nozzle 2 Claims, 12 Drawing Figures SAWIIEMR is I 33304150sum 2 OF 5 PATENTEDAPR 16 m4 3,804,150 SHEET m (If 5 In" 'I W MEUAPR :6mm 3,80%150 SHEEY 5 BF 5 1 APPARATUS FOR ELECTROSLAG REMELTING Thepresent invention relates to electrometallurgy and, more particularly,it relates to a method of electroslag remelting of consumable electrodesand to devices for effecting this method. More particularly, the invention relates toproduc'tion of ingots of high-quality electroslag metal.I

Well known in the art is a method of electroslag remelting of consumableelectrodes in moulds, in which a controllable gas atmosphere is createdabove the electroslag bath.

In this case saturation of the rernelted metal with deleterious gasesfrom the surrounding atmosphere is eliminated but requireddegasification of the metal is not achieved.

In addition,- when large ingots are produced by the method ofelectroslag remelting of high-dimension con summhs tq ssvtit tab ntstitqaessstoz H N and deleterious impurities (S, P, etc), it is necessary notonly to prevent the saturation of the remelte'd metal with gases fromthe surrounding atmosphere, but also to intensify the process ofdegasification, to increase the purity of the metal by excludingdeleterious impurities and" non-metallic inclusions, as well as toimprove the formation of the ingots of the electroslag remelting can notbe provided by means of the known method.

In present-day metallurgy there is also well known a method of gastreatment of molten metal consisting in blowing (bubbling) of the metalby gases and powders in a gas flow, thus somewhat improving the meltqualit-y. During the bubbling the mixing of the melt takes place onlynear the injected flow, while dead zones are formed in separate-portionsof the melt, in which the process of degasification and cleaning it fromthe deleterious and non-metallic inclusions (Pb, Sn, etc.) is

not adequate, and this deteriorates the quality of the obtained ingots.

SUMMARY OF THE INVENTION The principal object'of the invention is toprovide an improved method of electroslag remelting of consumableelectrodes wherein there is ensured intensive stirring (rotation) of themelt within the mould throughout the whole volume of this melt in theprocess of remeltin'g.

vice for effecting the proposed method.

These and other objects are attained due to the fact that in theproposed method of electroslag remelting of consumable electrodes theagents contributing to improvement of the quality of the ingot areinjected into the melt in such a manner that they cause rotation of thismelt.

It is expedient that the agents unjected into the slag and metalportions of the melt are blown in opposite directions. 1

To equalize the speeds of rotation of the slag and metal portions of themelt, the agents are preferably blown'in'to the slag portion of the meltunder a pressure which is lower than the pressure of the agents injectedinto the metal portion of the melt by a factor equal to The other objectof the invention is to provide a dethe difference between the specificgravity of the metal portion of the melt and the specific gravity of theslag portion of the melt.

In a mould having large dimensions it is expedient to create severalzones of rotation in a horizontal plane in the melt bath by blowing theagents into a corresponding number of the portions separately and inopposite directions in the adjacent portions.

The agents are preferably blown into' the slagportion of the meltdirectly under the consumable electrodes.

a metal being remelted wound inside the mould along the walls thereof.

The mould is preferably provided with at least one additional nozzlemade in the form ofa coil ofa melted material, the melting point ofwhich differs from the melting point of the material of the main coil,the additional nozzle being located respectively to the main coil andhaving a winding directed in opposition to the winding of the main coil.

In the mould at least at one level within the slag portion of the meltthere can be located at least one nozzle for injection of the agentsinto the melt made in the form of a branch pipe mounted into the lateralwall of the mould, the longitudinal axis of the branch pipe beingdirected tangentially to the mould wall.

It is expedient to mount several groups of pipe branches in the mouldwalls for injection of the agents into the melt with various angles ofinclination of their axes to the walls of the mould to provide forseveral zones of rotation of the melt within the mould with differentdirections of rotation in the adjacent zones, the number of the zonescorresponding to that of the groups of pipe branches.

In the mould having a widened upper portion the nozzles for blowing theagents into the slag portion are preferably arranged in the bottom ofthe upper widened portion of the mould directly'under the consumableelectrodes.

The bottom of the upper widened portion of the mould is preferablyprovided with removable inserts into which there are mounted the pipebranches for blowing the agents into the slag portion of the melt.

The nozzles for blowing the agents into the melt are preferably providedwith porous inserts of refractory metals.

The mould can be made sectional along a vertical line and having atleast two sections, in which case the mould walls in the place ofjointing the sections should be provided with av hermetically sealedchamber communicating through a slot with the bath of melt and through achannel with the source of agent improving the quality of the ingot.

It is expedient to make knurling at least on one plane forming the slot.

The above objects are also attained due to the fact that the consumableelectrode provided with a nozzle for blowing the agents into the melthas a nozzle in the form of a coil wound around the electrode and madeof the metal being melted.

The consumable electrode is preferably provided- BRIEF DESCRIPTION OFTHE DRAWINGS The invention will be apparent from the following detaileddescription of one embodiment thereof, reference being made to theaccompanying drawings, in

which:

FIG. 1 shows a device for electroslag remelting with a mould providedwith a nozzle in the form of a coil, according to the invention;

FIG. 2 is a sectional view taken along the line IIII in FIG. 1;

. FIG. 3 shows a device for electroslag remelting with a mould accordingto the invention provided with nozzles in the form of pipe branchesmounted into the wall of the mould;

FIG. 4 is a sectional view along the line IVIV in FIG. 3;

FIG. 5 shows a device for electroslag remelting with a mould providedwith nozzles in the form of pipe branches mounted by groups into thewall of the mould according to the invention;

FIG. 6 is a sectional view taken along the line VIVI in FIG. 5;

FIG. 7 is a device for electroslag remelting with a mould having awidened upper portion according to the invention;

FIG. 8 shows a device for electroslag remelting with a sectional mould,according to the invention;

FIG. 9 is a sectional view taken along the line IXIX in FIG. 8;

FIG. 10 shows a device for electroslag remelting with a consumableelectrode, according to the invention, the consumable electrode beingprovided with a nozzle in the form of a coil;v

FIG. 11 shows a device for electroslag remelting with a mould intendedfor simultaneously melting several separate ingots;

FIG. 12 is a sectional -XII in FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The device forelectroslag remelting (FIG. 1) consists of a water-cooled mould l and apan 2, pipe branches 3 for supply and removal of the cooling agents anda nozzle made in the form of a coil 4 wound within the mould 1 along thewalls thereof. The coil 4 is made of a melted material and is designedfor blowing into the slag portion 5 and into the metal portion 6 of themelt agents assisting in improving the quality of the ingots, forexample gases (Ar, I-Ie, N C0 etc.), a mixture of various gases (Ar 0etc.), gas-powder mixtures (Ar CaF etc. aerosoles and so on. Inaddition, the device is provided with a current supply source 7 oneterview' taken along the line XII- minal of which is connected to aconsumable electrode opposite to the winding of the main coil. Theadditional coils are also made of the material to be melted but theirmelting point should differ from the melting point of the main coil.

Shown in FIG. 2 is a section through the line I-I of the device forelectroslag remelting shown in FIG. I, in which there is illustrated theposition of the coil 4 and consumable electrode 8 relative to the wallsof the 5 mould 1 and also the disposition and shape of the cross sectionof the consumable electrode 8.

FIG. 3 shows a device for electroslag remelting which differs from themodification shown in FIGS. 1 and 2 in that it is provided with nozzlesfor injection of the agent made in the form of pipe branches 9 mountedinto the side walls of the mould 1. Depending on the cross section ofthe mould 1, the number of pipe branches 9 may be varied. The pipebranches 9 are disposed both within the zone of the slag portion 5 andthe Zone of metal portion 6 of the melt. In the device shown in FIGS. 3and 4 four pipe branches 9 are located along the diameter of the mould 1at one level within the zone of the slag portion 5 and four pipebranches 9 are located at one level within the zone of metal portion 6of the melt.

In addition, in FIG. 4 it is illustrated that the pipe branches 9 aremounted tangentially to the walls of the mould 1 and are located in sucha manner that the flows of agents blown through these pipe branchescause rotation of the slag portion 5 and the metal portion 6 of the meltin opposite directions.

FIG. 5 illustrates a modification of the device for electroslagremelting used for producing ingots of a large cross section. In thiscase, unlike the abovedescribed modifications of the remelting device.the mould l is provided with nozzles for injection of the agent whichare made in the form of pipe branches 11 mounted into the walls of themould l at several levels 10 along the height of the mould l. Thedistance between the levels 10 is selected so that during the wholeprocess of melting both the slag portion 5 and the metal portion 6 ofthe melt are blown with the agents.

The pipe branches 11, depending on the cross section of the mould, arecombined into several groups 12 (FIG. 6) in each of which thelongitudinal axes of the pipe branches 11 are inclined at such angles tothe wall of the mould 1 that in the process of injection of the agentsinto the melt through these pipe branches, formed within the melt areseveral zones 13 of rotation corresponding to the number of groups 12with opposite direction of rotation within the adjacent zones 13. FIG. 6shows four such zones 13.

FIG. 7 shows a version of the device for'electroslag remelting with amould having a widened upper portion 14 and a group of consumableelectrodes 15 located along the periphery of the upper portion 14. Inthis case the nozzles for feeding the agent into the melt made in theform of pipe branches 16 are preferably located in the bottom 17 of thewidened upper portion 14 of the mould directly under the consumableelectrodes 15. The pipe branches 16 are mounted in replaceable inserts18 which are mounted in the bottom 17. The supply of the agent to thepipe branches from the source (not shown in FIG. 7) of agent is effectedthrough a distributing unit 19 through channels 20.

The disposition of the pipe branches 16 for blowing the agents into theslag portion 5 of the melt directly under the consumable electrode 15allows the agent to be used not only for treatment of the molten metal21 but also the drops 22 and the thin film 23 of molten metal formed onthe meltable ends of the consumable electrodes 15.

To use the agent for treatment of the metal portion 6 of the melt, thelower portion of the mould l is preferably made in the form of acollector (not shown in FIG. 7) into the walls of which there aremounted nozzles for feeding the agents through the gap between the ingotand the internal wall of the collector into the melt, the above-saidnozzles being made in the form of pipe branches.

Shown in FIG. 8 is a version of the device for electroslag remeltingprovided with a sectional mould. In this case the nozzles for supplyingthe agent into the slag portion 5 and metal portion 6 of the meltconsist of slots 24 formed in the places of connection of the sections25 by the planes 26 thereof. The planes 26 have a knurling 27 (FIG. 9).In this construction the agent is supplied to the slots 24 from thesource (not shown) in FIGS. 8 and 9, through the channels 28 and throughthe hermetically sealed chambers 29 in the walls of the mould 1.

Shown in FIG. is a version of the device for electroslag remelting bymeans of a consumable electrode 8 provided with a nozzle for blowing anagent into the slag portion 5 of the melt made of the material beingmelted and shaped as a coil 30 which, unlike the version of. the deviceshown in FIGS. I and 2 is wound around the consumable electrode 8.

Shown in FIGS. 11 and I2 is a modification of the device for electroslagremelting provided with a mould I designed for melting several ingotssimultaneously.

In this case, unlike the above-described devices, the mould 1 isprovided with a bottom 31 having a central portion 32 protruding intothe mould 1, said central portion 32 having a cup 33 serving as acollector of the metal portion 6 of the melt and openings 34 (FIG. 12)used for shaping the ingot being melted and located along the peripheryof the bottom 31. The nozzles for blowing the agent into the melt aremade in the form of pipe branches 35 and are mounted into the walls ofthe protruding portion 32 of the bottom 31 at levels corresponding tothe position of the slag portion 5 and metal portion 6 of the melt.

The device for electroslag remelting shown in FIGS. 1 and 2 operates,according to the invention, in the following manner;

Prior to the process of electroslag remelting the mould 1 provided witha nozzle made of the material being melted in the form of a coil 4 isplaced onto the pan 2. A starting rod 36 is also placed on the pan 2,thereafter the consumable electrode 8 is inserted into the mould 1.After that an'electric current from the current source 7 is applied tothe consumable electrode 8 and the pan 2. From the source of agent (notshown in FIGS. I and 2) the agent is fed into the coil 4, while thecooling medium is fed into the jacket of the mould l and the pan 2. Thenmolten slag is poured into the mould l to form a slag portion of themelt (bath) until a current appears in the circuit: the consumableelectrode 8 the pan 2, which current causes melting of the electrode 8.

During the whole process of melting the consumable electrode 8 is fedinto the mould l at a rate equal to the rate of melting thereof. As fastas the consumable electrode melts off, molten metal is collected in themould l forming a metal portion 6 of the melt, said metal graduallysolidifying into an ingot 37. In the process of melting, the ingot 37 isbuiltup, the metal portion 6 and the slag portion 5 ascend within themould 1. In this case, simultaneously with the melting of the consumableelectrode 8, there is effected the melting of the coil 4, wound insidethe mould ll along the walls thereof, at a rate equal to the speed oflifting of the slag and metal portions 5 and 6 of the melt. The agentforced from the end of the coil 4, which is within the slag portion 5 ofthe melt during the whole process of melting, bubbles the slag portion 5and partially the metal portion 6 of the melt and simultaneously rotatesthem about the vertical axis of the mould I.

This makes it possible to considerably intensify the process ofdegasification and refining of the metal of the ingot 37.

The device for electroslag remelting shown in FIGS. 3 and 4 operatessimilarly to the device shown in FIGS. 1 and 2 with a single distinctionthat the ingot 37 in the process of melting is withdrawn from the mould1 at a speed which enables the slag and metal portions 5 and 6 of themelt during the whole process of melting to be in the mould l at thesame level at which is the agentinjecting nozzles shaped as pipebranches 9.

In addition, as the longitudinal axes of the pipe branches 9 locatedwithin the zone of slag portion 5 of the melt are directed opposite tothe longitudinal axes of the longitudinal axes of the pipe branches 9located within the zone of the metal portion 6 of the melt and aretangentially mounted into the walls of the mould 1, the agent blownthrough these pipe branches cause rotation of the slag and metalportions 5 and 6, respectively, in opposite directions.

The electroslag remelting device shown in FIGS. 5 and 6 operatessimilarly to the device shown in FIGS. l and 2, the differenceconsisting in that the agent blown through the nozzles shaped as pipebranches 11, mounted into the walls of the mould 1 and combined intofour independent groups 12.

The agent blown through the pipe branches ll simultaneously bubbles androtates the slag and metal portions 5 and 6 of the melt, in which caseeach group 12 of pipe branches ll builds up an independent zone 13 ofrotation of the melt. To mix the melt portions more intensively, thepipe branches 11 of the adjacent groups 12 are located so that the agentblown therethrough causes opposite rotation of the melt in the adjacentzones 13.

The device for electroslag remelting shown in FIG. 7 and designed forremelting of a group of consumable electrodes 15 operates similarly tothe device shown in FIGS. 3 and 4, however, in this case during thewhole process of melting the agent is blown through the pipe branches 16located in the bottom 17 of the widened portion 14 of the mould into theslag portion 5 of the melt directly under the consumable electrodes 15.In this case the flows of the agent injected into the melt andencountering the drops 22 and the thin film 23 of molten metal on themelted ends of the consumable electrodes 15 errode them and treat themetal (degasification and refining).

Furthermore, due to the fact that the bottom 17 of the widened upperportion 14 of the mould is cooled, a porous slag skin 38 is formed onthe bottom 17 in the places of disposition of the pipe branches 16 afterpouring the slag into the mould. The agent blown through the pipebranches 16 into the slag portion 5 of the melt, while passing throughthe slag skin 38, is pulverized into fine fractions and bubbles the slagand metal portions 5 and 6 of the melt, as well as the drops 22 and thefilm 23 of molten metal, by small blisters 39. This provides for abetter treatment of the melt by the agent, thereby improving the qualityof the ingot 37.

The electroslag remelting device shown in FIGS. 8 and 9 operatessimilarly to the device shown in FIGS. 3 and 4, the only differenceconsisting in that the agent injected into the slag and metal portions 5and 6 of the melt is blown by small blisters along the entire perimeterof the mould through the nozzles made in the form of slots 24communicating with a source of agent (not shown in FIGS. 8 and 9)through a hermetically sealed chamber 29 and channels 28.

The electroslag remelting device shown in FIG. 10 operates similarly tothe device shown in FIGS. 1 and 2, but in this case the agent isinjected into the slag portion 5 of the melt through a nozzle made ofmaterial being melted and shaped as a coil 30 wound on the consumableelectrode 8. In this case, during the melting the consumable electrode 8and the coil 30 are continuously fed into the mould l in which they aremelted together.

The electroslag remelting' device shown in FIGS. 11 and 12 operatessimilarly to the device shown in FIGS. 3 and 4, the only'differenceconsisting in that the agent is blown into the slag portion 5 and themetal portion 6 of the melt through nozzles made in the form of pipebranches 35 mounted into the walls of the protruding portion 32 of thebottom 31.

The agent blown through the pipe branches 35 simultaneously bubbles androtates the metal portion 6 of the melt not only in the openings 34shaping the ingot 37 but also in the cup 33 of the central portion 32 ofthe bottom 31. This provides for more complete treatment of thewholemetal portion 6 of the melt, thus improving the quality of theingot 37 being melted.

In the above-described modifications of the device the pipe branches forblowing the agent into the melt are provided with porous inserts 40(shown in the modification of the device in FIGS. 3 and 4) made ofrefractory materials (for example pourous W, Mo, etc.).

This makes it possible to inject the agent into the melt by fine streamsor mist and this increases the quality of treatment of the melt by theagent.

The advantages of the present invention consist in that during theelectroslag remelting of consumable electrodes according to the proposedmethod. the bubbling of the melt by an agent improving the quality ofthe ingot is associated with the rotation of the melt throughout thewhole volume of the mould and this makes it possible toconsiderably'intensify the process of degasification of the melt andcleaning of the same from deleterious impurities, non-metalinclusions'and fusible impurities as well as to improve the surface ofthe ingot which eventually increase the quality of the ingot beingmelted.

The rotation of the slag and metal portion of the melt in oppositedirections increases the path of the agent through the metal portion ofthe melt and assist in improvement of the quality of the ingot beingmelted.

The proposed method can be effected by means of devices built aroundknown electroslag remelting apparatus having a simple construction andfeatures by a low cost of manufacture, and this is still anotheradvantage of the proposed invention.

We claim:

'1. A vertically sectioned mould for an electroslag remelting process ofconsumable electrodes to form ingots, which process employs agentsinjected into the melt therein to improve the quality of said ingots,said mold comprising: at least two sections disposed in connectingrelationship; a hermetically sealed chamber in the walls of said moulddisposed along the line of connection of said sections; channel means inthe walls of said mould communicating said hermetically sealed chamberwith the agent; and means defining a slot communicating saidhermetically sealed chamber with the melt.

2. A mould as claimed in claim 1, in which one of the planes formingsaid slot is knurled. l

1. A vertically sectioned mould for an electroslag remelting process ofconsumable electrodes to form ingots, which process employs agentsinjected into the melt therein to improve the quality of said ingots,said mold comprising: at least two sections disposed in connectingrelationship; a hermetically sealed chamber in the walls of said moulddisposed along the line of connection of said sections; channel means inthe walls of said mould communicating said hermetically sealed chamberwith the agent; and means defining a slot communicating saidhermetically sealed chamber with the melt.
 2. A mould as claimed inclaim 1, in which one of the planes forming said slot is knurled.